CN201041735Y - Light-adjustable power control circuit - Google Patents
Light-adjustable power control circuit Download PDFInfo
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- CN201041735Y CN201041735Y CNU2007201436329U CN200720143632U CN201041735Y CN 201041735 Y CN201041735 Y CN 201041735Y CN U2007201436329 U CNU2007201436329 U CN U2007201436329U CN 200720143632 U CN200720143632 U CN 200720143632U CN 201041735 Y CN201041735 Y CN 201041735Y
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Abstract
The utility model relates to a control circuit of light adjusting electric power, and uses the methods of frequency modulation and amplitude modulation simultaneously. When the frequency change exceeds a set limitation range, the amplitude modulation type control is started instead to ensure that the drive voltage and the frequency of a lamp tube set are in the acceptable range of the lamp tube set, thereby minimizing the influence of the frequency interference.
Description
Technical field
A kind of control circuit of light modulation electric power is to utilize the frequency and amplitude modulation formula to control jointly to change output current to regulate light-source brightness.
Background technology
The topmost assembly of liquid crystal panel is polaroid and backlight module, utilizes backlight module to send and produces the needed light of picture, and the brightness of therefore adjusting the liquid crystal panel picture is adjusts the luminous brightness of backlight module; This brightness of backlight module is by Current Control, electric current is healed high brightness with regard to the height of healing, and the circuit of adjusting backlight module electric current comprises a dim signal source 1 as shown in Figure 1 at least, one pulse control unit 2, one switch element 5, one power source 4, one voltage transformation unit 6, one light tube group 7 and read the sampling unit 3 of a feedback signal to this pulse control unit 2 by this light tube group 7, the primary side whether this power source 4 is delivered to electric power voltage transformation unit 6 is controlled in the keying of this switch element 5, wherein this switch element 5 comprises a main switch assembly 51 and an auxiliary switch assembly 52, both turn-on cycles are staggered, and produce an operating voltage in these voltage transformation unit 6 secondary sides and make light tube group 7 luminous because of voltage difference starts, and the key of controlling this operating voltage is that this pulse control unit 2 provides the turn-on cycle signal of these switch element 5 actions, this pulse control unit 2 mainly is according to a reference voltage signal and a reference frequency signal, this reference voltage signal is to be converged by the dim signal that this feedback signal and this dim signal source 1 produce to form, and the novel amplitude modulation that is illustrated as of the known practical of Fig. 1 is adjusted circuit, this reference frequency signal mainly is to be connected in this pulse control unit 2 and to be produced by an electric capacity, because this capacitance size is fixed, time constant for charging and discharging is fixed, therefore the reference frequency signal among Fig. 1 is a fixed frequency, and the electric power turn-on cycle (duty cycle) that utilizes the adjustment reference voltage signal to change this switch element 5 reaches the effect of light modulation, but the electric power turn-on cycle (duty cycle) that changes this switch element 5 will make between the turn-on cycle of this main switch element 51 and auxiliary switch assembly 52 and produce long closing time (deadtime), can't reach zero voltage switching (zero voltage switching), and then produce loss; Another kind of known way is that frequency modulation type is adjusted circuit, be voltage is fixed and to be changed the frequency of this switch element 5 work and reach the light modulation effect, to cause these light tube group 7 luminance shortage or shorten the life-span if be higher or lower than these light tube group 7 frequency of operation own but adjust the power frequency that exports this light tube group 7 to, and when operating, high frequency will produce frequency interferences (interfering with each other) with other frequency of panel, therefore the frequency shift of frequency modulation type adjustment circuit is limited in scope and causes range of control limited, cause general user to feel that its adjustment capability is not good, and easily produce frequency interferences (occurring the strange waveform that disturbs on the picture), therefore two kinds of major control modes all remain the defective improved.
The utility model content
Because the mode of above-mentioned two classes control backlight module operating voltage all has its defective, thereby primary and foremost purpose of the present utility model is to provide a circuit that makes in regular turn in two ways, and is enough and reduce the purpose of known defect to reach range of control.
The utility model is a kind of control circuit of light modulation electric power, it is the mode of utilizing frequency and amplitude modulation simultaneously, then change amplitude modulation into behind the limited field that frequency variation surpass to be set, the driving voltage size that makes this light tube group and frequency are in the acceptable scope of this light tube group and can avoid the problem of frequency interferences; The utility model is that the turn-on cycle with a switch element is controlled a power source exports a light tube group to through a voltage transformation unit voltage, also comprise a sampling unit, one dim signal source, one regulon, one frequency modulation loop, one pulse control unit, this sampling unit reads a feedback signal from this voltage transformation unit secondary side, and the brightness settings signal that this feedback signal and this dim signal source provide confluxes and forms a conditioning signal, this conditioning signal is delivered to this regulon, this regulon has a reference voltage source, produce a reference voltage and this conditioning signal relatively, big or small sequential start one frequency modulation loop according to this conditioning signal, this frequency modulation loop is made up of this frequency limitation unit and this frequency generation unit, the restriction reference frequency signal is adjusted in certain limit, if the frequency of this reference frequency signal has reached critical that this frequency limitation unit sets, then this conditioning signal dividing potential drop forms a reference voltage signal in addition, make this pulse pulse control unit can utilize this frequency modulation loop and this reference voltage signal and produce the turn-on cycle of this switch element, to regulate the brightness of this light tube group.
Description of drawings
Fig. 1 is the calcspar that known amplitude modulation is adjusted circuit.
Fig. 2 is a calcspar of the present utility model.
Fig. 3 is an enforcement illustration of the present utility model.
Fig. 4 is the enforcement illustration of the utility model regulon.
Fig. 5 is node voltage figure of the present utility model ().
Fig. 6 is node voltage figure of the present utility model (two).
Fig. 7 is node voltage figure of the present utility model (three).
Embodiment
The utility model is a kind of control circuit of light modulation electric power, it is the electric power turn-on cycle correction that is applied to an inverter, this inverter comprises that one provides the pulse control unit 2 of electric power turn-on cycle, one provides the power source 4 of this inverter light modulation electric power, one determines the switch element 5 of the conducting sequential of this power source 4 with this electric power turn-on cycle, and one originate 4 output powers to drive the voltage transformation unit 6 of rear end load according to conducting sequential power conversion, wherein this electric power turn-on cycle is to revise according to this voltage transformation unit 6 or load feedback power user mode, and on this feedback loop, connect and establish a control circuit, see also Fig. 2, this control circuit includes a dim signal source 1, one sampling unit 3, one regulon 8 and a frequency modulation loop, reach electric power turn-on cycle (duty cycle) and the frequency of adjusting these switch element 5 conductings, the electric current that exports a light tube group 7 with change to is adjusted brightness, wherein this regulon 8 connects a frequency modulation loop and this pulse control unit 2, and enable this frequency modulation loop in regular turn and produce a reference voltage signal to reach the purpose that has frequency and amplitude modulation control simultaneously, this frequency modulation loop more comprises a frequency limitation unit 9 and a frequency generation unit 10; This pulse control unit 2 is being controlled the electric power turn-on cycle of this switch element 5, the electric power turn-on cycle of this switch element 5 influences between this power source 4 and this voltage transformation unit 6 whether conducting, and then electric power is sent to the light tube group 7 of these voltage transformation unit 6 secondary sides, make this light tube group 7 luminous, and a sampling unit 3 reads a feedback signal from these voltage transformation unit 6 secondary sides, this feedback signal is confluxed into a conditioning signal with the brightness settings signal that this dim signal source 1 produces in addition, this conditioning signal is received by a regulon 8, this regulon 8 is to enable this frequency modulation loop in regular turn and produce this reference voltage signal according to the size of this conditioning signal, this reference voltage signal is to input to this pulse control unit 2 to regulate the work period of these pulse control unit 2 outputs, this frequency modulation loop is to include a frequency limitation unit 9 and a frequency generation unit 10, this frequency generation unit 10 is to produce the frequency of operation that a reference frequency signal forms the first electric power turn-on cycle, this frequency limitation unit 9 is to obtain this FM signal to the utlity model has the effect of utilizing frequency and amplitude modulation control simultaneously in order to set the frequency range scope of these frequency generation unit 10 output reference frequency signals, to make.
See also Fig. 3 and Fig. 4, Fig. 3 is an enforcement illustration of the present utility model, when this pulse control unit 2 produces one first electric power turn-on cycle and makes this switch element 5 of electric power mat of this power source 4 and voltage transformation unit 6 export this light tube group 7 to, this sampling unit 3 reads a feedback signal from these voltage transformation unit 6 secondary sides, and confluxes into a conditioning signal with the brightness settings signal of this dim signal source 1 output and import this regulon 8; The embodiment of this regulon 8 as shown in Figure 4, by one first comparer 82, one second comparer 83, one reference voltage source 81 and a plurality of resistance are formed, wherein an end of this first comparer 82 and second comparer 83 is imported the reference voltage of these reference voltage source 81 outputs, the other end of this first comparer 82 is imported this conditioning signal and this reference voltage comparison and is exported a FM signal, this conditioning signal utilizes this resistance R 3 and resistance R 4 dividing potential drops to import the other end of this second comparer 83, this second comparer, 83 outputs, one reference voltage signal when this resistance R 3 and resistance R 4 dividing potential drops are big than this reference voltage, this reference voltage signal influences the electric power turn-on cycle (duty cycle) of these pulse control unit 2 outputs; Please consult Fig. 3 again, this FM signal is delivered to this frequency modulation loop, this frequency modulation loop comprises this frequency limitation unit 9 and this frequency generation unit 10, this frequency generation unit 10 is that a capacitor C 1 is connected in this pulse control unit 2, utilize discharging and recharging of this capacitor C 1 to produce a reference frequency signal, and form a reference frequency with the speed of discharging and recharging of this capacitor C 1, and this frequency limitation unit 9 comprises a capacitor C 2, resistance R 2 and transistor Q3, this frequency limitation unit 9 is the sizes by these capacitor C 2 impedances, and the size of current of the collection utmost point when limiting this this transistor Q3 that flows through and working in saturation area, form the frequency limitation border of this frequency generation unit 9, the gate of this transistor Q3 connects this resistance R 2 and this regulon 8, this transistor Q3 collection utmost point connects this capacitor C 2 and this transistor Q3 is in parallel with this frequency generation unit 10 with capacitor C 2, this FM signal is controlled the size of current of this transistor Q3 collection utmost point, the electric current that makes this capacitor C 1 of flowing through reduces because of this transistor Q3 and capacitor C 2 shuntings, and then change the speed that this capacitor C 1 discharges and recharges and limit the frequency range of this reference frequency signal, this reference frequency signal influence 2 outputs of this pulse control unit electric power turn-on cycle (duty cycle) frequency and produce the second electric power turn-on cycle that frequency is different from this first electric power turn-on cycle, this FM signal is too high again make this transistor Q3 reach full closing after, the electric current of this transistor Q3 collection utmost point then stops to rise, form the frequency limitation border of this reference frequency signal, make this pulse control unit 2 produce one the 3rd electric power turn-on cycle, to regulate the brightness of this light tube group 7 with this reference frequency signal and this reference voltage signal.
See also Fig. 3 and Fig. 5 to Fig. 7, the node that in the circuit of Fig. 3, has A to E, Fig. 5 to Fig. 7 is the voltage waveform of each node in the different operating situation, the A point is the voltage waveform of reference frequency signal, the E point is the waveform of this conditioning signal, B point and C point are respectively the gate voltage waveform of this main switch assembly 51 and auxiliary switch assembly 52, and the D point is the waveform of this voltage transformation unit 6 of output; The conditioning signal of E is 0 among Fig. 5, therefore these frequency limitation unit 9 work make this frequency generation unit 10 produce an initialization frequency, the predeterminated frequency that this initialization frequency is a frequency generation unit 10 deducts the frequency default value of frequency limitation unit 9, and the initialization frequency that the electric voltage frequency that B point and C are ordered and this frequency generation unit 10 provide is identical, and make this main switch assembly 51 and the 52 staggered conductings of auxiliary switch assembly, and the electric voltage frequency that this voltage transformation unit 6 primary side D are ordered is also identical with B point voltage frequency; The conditioning signal that E is ordered among Fig. 6 raises because of feedback signal and brightness settings signal conflux, thereby this regulon 8 stops this frequency modulation loop and reference frequency signal frequency that A is ordered rises, the electric voltage frequency that B point, C point and D are ordered also with rising; Conditioning signal voltage among Fig. 7 rises more, make these regulon 8 these reference voltage signals of output make this pulse control unit 2 change the electric power turn-on cycle (duty cycle) of output, the voltage cycle that B point and C are ordered obviously shortens, and then changes the voltage waveform of this voltage transformation unit 6 of flowing through; Thereby the utlity model has the function of frequency and amplitude modulation, and the function that can enable frequency and amplitude modulation in regular turn is to reach zero voltage switching and adjust the effect of brightness in the frequency of operation of this light tube group 7.
Above-mentioned explanation and graphic in the capacitor C 2 of this frequency limitation unit 9 also can change a resistance into; or other can reach the assembly of shunting limit frequency effect; and the transistor Q3 of frequency limitation unit 9 also can change an operational amplifier (OP) into; or other can have the assembly of amplification effect; though the utility model is described in detail by preferred embodiment; but the above can not limit the utility model; any those skilled in the art; variation and the modification in not breaking away from spirit and scope of the present utility model, done; all should be encompassed in the technology category of the present utility model, therefore protection domain of the present utility model should with accompanying claim the person of being defined be as the criterion.
In sum, the utility model that the utility model is more known has been promoted above-mentioned functions, should fully meet the legal innovation patent key element of novelty and progressive, therefore file an application in accordance with the law, earnestly ask your office and check and approve the utility model patent application case, to encourage utility model, to feeling moral just.
Claims (9)
1. the control circuit of a light modulation electric power, it is the electric power turn-on cycle correction that is applied to an inverter, described inverter comprises that one provides the pulse control unit (2) of electric power turn-on cycle, one provides the power source (4) of described inverter light modulation electric power, one determines the switch element (5) of the conducting sequential of described power source (4) with described electric power turn-on cycle, and one according to conducting sequential power conversion source (4) output power to drive the voltage transformation unit (6) of rear end load, wherein said electric power turn-on cycle is to revise according to described voltage transformation unit (6) or load feedback power user mode, and on described feedback loop, connect and establish a control circuit, it is characterized in that described control circuit includes:
One sampling unit (3) is in order to obtain a feedback signal;
One frequency modulation loop, be to connect described pulse control unit (2) and determine described electric power turn-on cycle, described frequency modulation loop includes a frequency limitation unit (9) and a frequency generation unit (10), described frequency generation unit (10) is to produce the frequency of operation that a reference frequency signal forms the first electric power turn-on cycle, and described frequency limitation unit (9) is the frequency range scope in order to the reference frequency signal of setting described frequency generation unit (10);
One regulon (8), described regulon (8) has a reference voltage and described feedback signal is relatively exported the frequency range scope that a FM signal to described frequency modulation loop determines the described reference frequency signal of described frequency limitation unit (9) setting, make described pulse control unit (2) produce one second electric power turn-on cycle so that form to feedback to revise, to regulate the brightness of light tube group (7).
2. the control circuit of light modulation electric power according to claim 1, it is characterized in that described regulon (8) is connected with a dim signal source (1), and to obtain that a brightness settings signal and described feedback signal conflux be that a conditioning signal is relatively exported FM signal with reference voltage again.
3. the control circuit of light modulation electric power according to claim 1, it is characterized in that described conditioning signal makes described reference frequency arrive its frequency range range boundary, then described conditioning signal dividing potential drop is exported a reference voltage signal in addition to described pulse control unit (2), makes described pulse control unit (2) produce one the 3rd electric power turn-on cycle with described reference frequency signal and described reference voltage signal.
4. the control circuit of light modulation electric power according to claim 1, it is characterized in that, described regulon (8) is by one first comparer (82), one second comparer (83), one reference voltage source (81) and a plurality of resistance are formed, one end of wherein said two comparers is imported the reference voltage of described reference voltage source (81) output, the other end and described reference voltage that described a plurality of resistance is imported described two comparers with described conditioning signal dividing potential drop compare, and by described first comparer (82) output one FM signal, described second comparer (83) output one reference voltage signal.
5. the control circuit of light modulation electric power according to claim 4, it is characterized in that, described second comparer (a 83) wherein input is by described conditioning signal dividing potential drop, another input is described reference voltage, when the dividing potential drop of described conditioning signal during less than described reference voltage, described second comparer (83) output electronegative potential.
6. the control circuit of light modulation electric power according to claim 1 is characterized in that, described frequency generation unit (10) be at least one capacitance series in described pulse control unit (2), form described reference frequency signal by described capacitor charge and discharge.
7. the control circuit of light modulation electric power according to claim 1, it is characterized in that, described frequency limitation unit (9) is by a transistor, one to be serially connected with described transistor base in parallel with described frequency generation unit (10) with an electric capacity with the resistance between the described regulon (8), described electric capacity is connected in the described transistorized collection utmost point, the size of described FM signal is controlled described transistorized conducting and is influenced the size of current of the described electric capacity of flowing through, thereby divides the described frequency generation unit of flow restriction (10) to produce the frequency range scope of described reference frequency signal with described frequency generation unit (10).
8. the control circuit of light modulation electric power according to claim 1, it is characterized in that, described frequency limitation unit (9) is by a transistor, one be serially connected with between described transistor base and described regulon (8) resistance and one with described frequency generation unit (10) electric capacity in parallel, described electric capacity is connected in the described transistorized collection utmost point, the size of described FM signal is controlled described transistorized conducting and is influenced the size of current of the described electric capacity of flowing through, thereby the reference frequency signal scope of dividing the described frequency generation unit of flow restriction (10) to produce with described frequency generation unit (10).
9. according to the control circuit of claim 7 or 8 described light modulation electric power, it is characterized in that, described frequency limitation unit (9) is the size by condensance, and the size of current of the collection utmost point when limiting the described described transistor of flowing through and working in saturation area forms the frequency limitation border of described frequency generation unit (10).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007201436329U CN201041735Y (en) | 2007-04-20 | 2007-04-20 | Light-adjustable power control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007201436329U CN201041735Y (en) | 2007-04-20 | 2007-04-20 | Light-adjustable power control circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201041735Y true CN201041735Y (en) | 2008-03-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007201436329U Expired - Fee Related CN201041735Y (en) | 2007-04-20 | 2007-04-20 | Light-adjustable power control circuit |
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| Country | Link |
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| CN (1) | CN201041735Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103139983A (en) * | 2011-11-30 | 2013-06-05 | 夏普株式会社 | LED drive circuit and LED illumination unit |
| CN108601186A (en) * | 2018-06-26 | 2018-09-28 | 深圳市同洁科技有限公司 | A kind of lamp tube drive circuit |
-
2007
- 2007-04-20 CN CNU2007201436329U patent/CN201041735Y/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103139983A (en) * | 2011-11-30 | 2013-06-05 | 夏普株式会社 | LED drive circuit and LED illumination unit |
| CN103139983B (en) * | 2011-11-30 | 2015-04-01 | 夏普株式会社 | LED drive circuit and LED illumination unit |
| CN108601186A (en) * | 2018-06-26 | 2018-09-28 | 深圳市同洁科技有限公司 | A kind of lamp tube drive circuit |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20080326 Termination date: 20100420 |